American Sign Language (Ameslan or ASL) is the manual-visual language used by deaf communities in the Unites States since the early 19th century. We are proceeding on the theory that by examining a language in another modality in which speech and hearing are absent, one can get some idea of which traits in a language are truly universal and which are peculiar to spoken language. The first of two research areas explores the structure of Ameslan at what would correspond to the phonological level of spoken languages. Several of the experiments are modelled after Miller and Nicely's classic study (1955) of the perception of English consonants. With congenitally deaf Ameslan signers of deaf parents, one study attempts to establish a distinctive feature matrix of the Ameslan parameter of hand location. Fourteen location primes are systematically varied across three levels of each of the other three sign parameters. Next, these nonsense signs are mixed with visual noise and presented for identification of location. Scaling procedures and clustering analysis will be applied to the resulting confusion matrices. Another experiment is a validation study of the previous findings using reaction time rather than identification responses as the dependent variable. We will also conduct experiments on short-term memory for the parameters of nonsense signs, much as Wickelgren (1966) did for English consonants. A related endeavor now in progress is computerizing the dictionary of American Sign Language (Stokoe et al., 1965). The second research area is concerned with timing in sign language. How do the component variables of sign rate alter and interact when a signer alters his rate? What is the counterpart in sign of pausing in speech? Are these signed pauses motivated directly, as in speech, by syntactic structure? If so, can we derive a constituent analysis of a sentence in Ameslan from its pause distribution and will this provide a reasonable description of the phrase structure of the sentence?